this.rankMap = rankMap;
  }

  @Override
  public int compare(T left, T right) {
    return rank(left) - rank(right); // safe because both are nonnegative
  }

  private int rank(T value) {
    Integer rank = rankMap.get(value);
    if (rank == null) {
      throw new IncomparableValueException(value);
    }
    return rank;
  }

  @Override
  public boolean equals(@CheckForNull Object object) {

    }

    /** Equivalent to {@code newReentrantReadWriteLock(rank, false)}. */
    public ReentrantReadWriteLock newReentrantReadWriteLock(E rank) {
      return newReentrantReadWriteLock(rank, false);
    }

    /**
     * Creates a {@link ReentrantReadWriteLock} with the given fairness policy and rank. The values

  abstract Map<Integer, Double> multipleQuantiles(
      Collection<Integer> indexes, int scale, double[] dataset);

  static double getMinValue(double[] array, int from) {
    // This is basically a copy of com.google.math.Rank#getMinValue, with a small change in the
    // method signature: we always search to the end of the array.
    int min = from;
    for (int i = from + 1; i < array.length; i++) {
      if (array[min] > array[i]) {

  abstract Map<Integer, Double> multipleQuantiles(
      Collection<Integer> indexes, int scale, double[] dataset);

  static double getMinValue(double[] array, int from) {
    // This is basically a copy of com.google.math.Rank#getMinValue, with a small change in the
    // method signature: we always search to the end of the array.
    int min = from;
    for (int i = from + 1; i < array.length; i++) {
      if (array[min] > array[i]) {

    this.rankMap = rankMap;
  }

  @Override
  public int compare(T left, T right) {
    return rank(left) - rank(right); // safe because both are nonnegative
  }

  private int rank(T value) {
    Integer rank = rankMap.get(value);
    if (rank == null) {
      throw new IncomparableValueException(value);
    }
    return rank;
  }

  @Override
  public boolean equals(@CheckForNull Object object) {

    final T value;
    final int rank;

    Composite(T value, int rank) {
      this.value = value;
      this.rank = rank;
    }

    // natural order is by rank only; the test will compound() this with the
    // order of 't'.
    @Override
    public int compareTo(Composite<T> that) {
      return Ints.compare(rank, that.rank);
    }

    final T value;
    final int rank;

    Composite(T value, int rank) {
      this.value = value;
      this.rank = rank;
    }

    // natural order is by rank only; the test will compound() this with the
    // order of 't'.
    @Override
    public int compareTo(Composite<T> that) {
      return Ints.compare(rank, that.rank);
    }